Composite structures are used in a wide variety of applications due to their high strength-to-weight ratio, good corrosion resistance, and other favorable properties relative to metallic structures. In aircraft construction, composites are used in increasing quantities to form the wings, the horizontal and vertical tail, the fuselage, and other components. For example, the fuselage of an aircraft may be manufactured by the end-to-end assembly of multiple composite barrel sections. Each barrel section may be formed by laying up composite plies over a plurality of longitudinal composite stringers supported on a rotatable layup mandrel. After curing, the barrel section may be removed from the layup mandrel and mounted on an assembly fixture to allow for the installation of internal mating structure. The opposing ends of the barrel section may be attached to the assembly fixture in a manner allowing for rotation of the barrel section. During installation of the internal mating structure, a series of axially-spaced circumferential frames may be installed inside the barrel section to maintain the cross-sectional shape of the barrel section and to support hoop loads imposed on the barrel section during cabin pressurization.
The circumferential frames may be placed in contact with the inner surfaces of the barrel section at a plurality of discrete mounting locations where the circumferential frames may be secured to the barrel skin using mechanical fasteners. However, when the barrel section is mounted on the assembly fixture, the portion of the barrel section located between the opposing ends is unsupported, causing the barrel section to assume an as-built configuration that deviates from the as-designed configuration. As a result of the deviation, unplanned gaps may occur at mounting locations where the circumferential frames are to be attached to the skin. For mounting locations wherein the gap size exceeds a predetermined maximum, shims must be installed prior to fastening the circumferential frames to the barrel skin. Unfortunately, the need to install a large quantity of unplanned shims significantly adds to the production flow time. At frame locations where the gaps are excessively large, it may be necessary to rework the circumferential frame, which further adds to the production flow time.
As can be seen, there exists a need in the art for a system and method for reducing the deviation between the as-built configuration and the as-designed object configuration of the barrel section as a means to reduce shimming and potential rework.